In a distant future, Japan is devastated by the catastrophic 'Rusty Wind,' turning the land into a desert wasteland and shattering society. When his mentor succumbs to the rust, the adventurous Bisco Akahoshi sets out across the sandy expanse to acquire the elusive Rust Eater mushroom, believed to possess healing properties. Teaming up with the charming physician Milo, they must navigate the harsh terrain and outwit their companions to survive the perilous journey home.